The prior art systems employing video image displays of signals from infrared sensed targets have a number of disadvantages.
One disadvantage consists of a loss of detail in displayed scenes when unusually hot targets of extended size are present.
Another disadvantage of such prior art systems is the need for a manual gain control in order to cover the wide range of infrared signal levels between targets having large temperatures and targets having the smallest possible discernable temperature.
A further disadvantage of such prior art systems is manifested in a multiple target situation wherein large and small temperature radiating targets are simultaneously present in the scene. In such case it is necessary for the operator of the system to manually attenuate the overall scene signals in order to acquire total scene information, and in such instance, information from low temperature target radiations is lost.